This story is an anti-narrative, designed to undermine the reader's assumptions of what a love-story from a female author should be. The reader expects more of the novel to revolve around the man, but instead, Laurence chooses to limit the scope of the romance to only a summer, leaving the majority of the story as a story about the woman alone. That's the main argument of the narrative, that Rachel Cameron is a protagonist even though she is a woman, and that her growth and success in life are to be celebrated in their own respect, not just as a tangent to a story about men.
This focus on female without male draws Cameron's attention to her relationship with her mother, and therefore to the difficulties for women existing in a culture of this type. Cameron finds herself fighting for meaning in a world that only shows meaning through romance. She finds herself fighting for community in a world that has created petty, disappointing women in her life, not least of which are those in positions of authority.
These thematic interpretations might be combined in this way: Margaret Laurence succeeds in highlighting the reader's social and psychological assumptions about women by subverting common tropes and by highlighting isolation in Rachel Cameron's life. In other words, she manages to make the reader treat the character as a complex, intensely human person, even though she is a woman.
